I. BACKGROUND
ImageMagick is a suite of image manipulation tools (animate, composite,
conjure, convert, display, identify, import, mogrify and montage) that
are sometimes used by other applications for processing image files.
For more information about ImageMagick, visit the vendor's site at the
following URL.
http://www.imagemagick.org/
II. DESCRIPTION
Remote exploitation of multiple integer overflow vulnerabilities in
ImageMagick, as included in various vendors' operating system
distributions, allows attackers to crash applications using the
ImageMagick library, and in some cases, execute arbitrary code.
Several integer overflow vulnerabilities have been identified in
ImageMagick's handling of various file formats. By creating a specially
crafted DCM, DIB, XBM, XCF, or XWD image file, an attacker can cause a
heap buffer of insufficient size to be allocated. This results in a
heap-based buffer overflow.
III. ANALYSIS
Exploitation of these vulnerabilities allows an attacker to crash the
programs using ImageMagick library, or execute arbitrary code in the
context of the user.
One way of exploiting these vulnerabilities is to persuade a targeted
user to open a malicious image file with a program that utilizes the
ImageMagick library.
As the tools that are part of ImageMagick are sometimes used as helper
tools by other applications, this user may be the same as the web
server user. This scenario is somewhat more severe than the previously
described attack vector since the image processing can occur
automatically.
IV. DETECTION
iDefense Labs confirmed that ImageMagick version 6.3.4 is vulnerable. It
is suspected that other versions of ImageMagick are also vulnerable.
V. WORKAROUND
Exposure to some of these vulnerabilities can be mitigated by moving or
deleting the related module files. The file locations may vary between
distributions. The globbing expressions listed below correspond to a
Red Hat Linux system.
/usr/lib/ImageMagick-*/modules*/coders/dcm.*
/usr/lib/ImageMagick-*/modules*/coders/dib.*
/usr/lib/ImageMagick-*/modules*/coders/xbm.*
/usr/lib/ImageMagick-*/modules*/coders/xcf.*
/usr/lib/ImageMagick-*/modules*/coders/xwd.*
VI. VENDOR RESPONSE
The ImageMagick maintainers have addressed these vulnerabilities with
the release of version 6.3.5-9. More information is available from the
following URL.
http://studio.imagemagick.org/pipermail/magick-announce/2007-September
/000037.html
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2007-4986 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which
standardizes names for
security problems.
VIII. DISCLOSURE TIMELINE
09/04/2007 Initial vendor notification
09/05/2007 Initial vendor response
09/19/2007 Coordinated public disclosure
IX. CREDIT
These vulnerabilities were reported to iDefense by regenrecht.
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http://labs.idefense.com/methodology/vulnerability/vcp.php
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http://labs.idefense.com/
X. LEGAL NOTICES
Copyright © 2007 iDefense, Inc.
Permission is granted for the redistribution of this alert electronically. It may not be edited in
any way without the express written consent of iDefense. If you wish to reprint the whole or any
part of this alert in any other medium other than electronically, please e-mail customer service for
permission.
Disclaimer: The information in the advisory is believed to be accurate at the time of publishing
based on currently available information. Use of the information constitutes acceptance for use in
an AS IS condition. There are no warranties with regard to this information. Neither the author nor
the publisher accepts any liability for any direct, indirect, or consequential loss or damage
arising from use of, or reliance on, this information.
